The configuring of nodes in a communication switching network, such as employed by International Business Machines in their RS/6000 Workstation architecture, is typically performed statically, with each node preassigned an addressed before the switch network is utilized. However, such static configuring of network nodes is inherently inflexible and adds complexity to a network installation process.
Conventionally, the nodes of a network can also be configured by mapping the topology of the network through either the exchange of information on a separate network, or through the passive monitoring of traffic on the network. Clearly, the addition of a separate, second network to determine topology of a first network adds cost and complexity to a system. Further, passive monitoring of traffic on a network can require an unacceptably long delay before the network topology is known.
Fiber distributed data interface (FDDI) and token ring both use neighbor notification methods where nodes send packets that are only received by their neighboring nodes. This approach allows individual nodes to communicate only with their direct neighbors, but by monitoring traffic on the network, a remotely located managing node can discover the neighbors of all other nodes in the network. This method means waiting for all nodes of the ring to transmit to their neighbors, often requiring as long as thirty seconds to complete, which can comprise an unacceptable latency. Further, this method requires that the managing node be disposed within the ring itself.
As more computer systems incorporate interconnection or switching networks as a highbandwidth fault-tolerant means of connecting processors and input/output (I/O), a quick and inexpensive approach to identifying and configuring the nodes of the network becomes important. The use of such interconnection networks in personal computer (PC) systems places an even stronger requirement on the initialization approach; i.e., it should automatically recognize new devices and properly configure them, while still being quick and inexpensive. With personal computers moving to plug and play capabilities, it is only a matter of time before workstations must be able to self-identify their internal interconnection topology. The present invention addresses this need by providing an approach that allows network self-identification.
More particularly, an approach for configuring nodes is needed that can explore an interconnection network having unknown topology using the network itself. Further, an approach is desired which allows the searching of unknown portions of the network so that new devices can be discovered, along with a method for configuring nodes that allows multiple managing nodes to remotely initialize the network, without race conditions causing errors or conflicts. The present invention addresses each of these needs.